Recently the safety of the cars has increased due to the installation of various types of sensors and to related electronic control systems. Tires are also under study to avoid wear and possible explosions, which can of course create problems to motor vehicle occupants.
Normally the deformation of the tread is measured by application of sensors to the tires, and measurement systems provide data related to the contact condition of the tire with the road.
A method that uses the structure of the tire as a sensor is described by the article of A. Todoroki, S. Miyatani, and Y. Shimamura, Wireless Strain Monitoring Using Electrical Capacitance Change Of Tire: Part I With Oscillating Circuit”, Smart Material And Structure, Institute of Physics Publishing, No. 12, pp. 410-16, 2003. The article describes a measurement method of tire deformation that uses the tire steel wires as electrodes of a capacitor. The steel wires are connected to an oscillating circuit of the LC type, and the frequency variations of the oscillator correspond to the variations of the capacitor capacity.